RAD 104 prelims Flashcards
What is the FFD in general radiography
40 - 42 inches
Is the exactness of representation of the patients anatomy on a radiographic image
Radiographic image quality
The degree of overall blackening of a radiograph
Amount of blackness on a given area of radiograph
Radiographic density
Combination of setting selected on the control panel
Radiographic technique
Uses light to expose the film
Intensifying screen
Few variation of black
high contrast
The OD that is inherent in the base of the film
Base density
Process of taking a radiograph
Radiography
Acceptable range for optical density
0.25 - 2.0
What is the FFD in the radiography of thoracic cavity
72 inches
Principal source of noise
Scattered radiation
Most important characteristics of radiographic image
spatial resolution
contrast resolution
noise
artifact
Primary control of xray quality (beam penetrability)
kilovoltage peak kVp
Too dark = high density = OVEREXPOSED
Too light = low density = UNDEREXPOSED
A quantitative factor that when combined with mA determines the exposure rate
Exposure time
Device used to reduce the intensity of scatter radiation in the remnant xray beam
Grid or Bucky
Blackening
Density
Tools for increasing radiographic quality
Patient positioning
Image receptor
Selection of exposure factors
Two types of radiation
Ionizing
non-ionizing
2 categories of image quality
Photographic aspect and Geometric Aspect
Interconnects resolution and noise
Speed
Noise that is caused by few xray
Quantum mottle
Measured from the focal spot to the recording medium (xray film) and is called FOCAL - FILM DISTANCE (FFD)
Distance
Black
Penetration
Controls optical density
mAs
Noise that is inherent to Intensifying screen
Structure mottle
Process of taking a photograph
Photography
milliamperage x exposure time
mAs
kVp controls Contrast
mAs controls Density
Capability of film to absorb light
Film speed
Fog density
0.04
Factor that selects the length of the time for an exposure
Exposure time
Random fluctuations of the optical density of the radiograph
Speckled background on image
Grainy or uneven appearance of an image
Noise
Variation of density level
Goal to make detail visible
Contrast
4 significant factors
kVp mA exposure time SID
Ability to image small objects that have high subject contrast
Spatial resolution
Acceptable base density
0.14
Ability to distinguish anatomical structures of similar subject contrast
Contrast resolution
Is the most effective method for reducing the scattered radiation
Collimation
Law that states that radiation intensity will vary inversely with the square of the distance from the source
Inverse square law
Determines number of xray produced
Radiation quantity
milliamperage mA
Many variation of black
Low contrast
ALARA
As low as reasonably achievable
Qualities of a good photograph
Composition
Focus
Evokes emotion or Tells a story
The development of the silver grains that contain no useful information
Fog density
Acceptable base + fog density
0.18
White
Absorption
Less precise term for spatial and contrast
Detail
Clarity and sharpness of structural lines
Definition
Factors that influence and determine the quantity and quality of xrays to which the patient is exposed
Exposure Factor
The use of Intensifying screen decreases the patient dose by?
15 - 20
Undesired change in the size and shape of the anatomic part
Distortion
Is a systematic procedure used by the radiographer to accomplish task of producing a high quality radiograph
Radiographic technique
Ejects electron using IR that results to scattered radiation
Compton interaction
Capability of screen to produce light
Screen speed
FFD is also called
Source - Image Distance (SID)
Ability to image 2 separate objects and visually distinguish one from the other
Resolution
What causes noise
Insufficient number of xrays
Uniform signal produced by scattered radiation
Faster screen speed
